US2107901A - Electrical insulation material - Google Patents

Electrical insulation material Download PDF

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Publication number
US2107901A
US2107901A US6485636A US2107901A US 2107901 A US2107901 A US 2107901A US 6485636 A US6485636 A US 6485636A US 2107901 A US2107901 A US 2107901A
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US
United States
Prior art keywords
asbestos
insulation material
combined
sheet
cellulose acetate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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Inventor
Carl F Obermaier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Co
Original Assignee
General Electric Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US57643331 external-priority patent/US2038378A/en
Application filed by General Electric Co filed Critical General Electric Co
Priority to US6485636 priority Critical patent/US2107901A/en
Application granted granted Critical
Publication of US2107901A publication Critical patent/US2107901A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/02—Disposition of insulation
    • H01B7/0208—Cables with several layers of insulating material
    • H01B7/0216—Two layers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/31504—Composite [nonstructural laminate]
    • Y10T428/31652—Of asbestos
    • Y10T428/31659—With cellulosic layer
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
    • Y10T442/50—FELT FABRIC
    • Y10T442/59—At least three layers

Definitions

  • This invention relates to electrical insulation 5 material and to methods of making the same.
  • Asbestos listing which is tape Woven from iine asbestos yarn, has been used for some time in the electrical industry as insulation material. This tape has been diiiicult and expensive to'manufacture especially in thin sheets. -Such material as well as the so-called asbestos paper tape possesses very little strength.
  • asbestos either felted or in the form of a ne paperlike material in sheet form is combined in a suitable manner with a cellulosic material, such as, for example, regenerated cellulose, known in the trade for instance as cellophane, or a cellulose derivative such as cellulose acetate.
  • a cellulosic material such as, for example, regenerated cellulose, known in the trade for instance as cellophane, or a cellulose derivative such as cellulose acetate.
  • the cellulosic material not only lends strength to the asbestos but the combined material is rendered high in dielectric value due to the cellulosic material and heat resistant due to the felted asbestos. It may be made in the form of sheets, tape, windings, etc. and may be impregnated or coated with such materials as insulating varnishes, synthetic resins and the like, making the whole better in insulation value and eliminating subsequent coating operations Where the material is used for example as a tape in insulating windings of electrical apparatus. In certain cases, the material may consist of a single sheet of cellulosic material combined on one or both sides thereof with asbestos or the asbestos may be sandwiched between a plurality of sheets of cellulosic material and suitably combined therewith.
  • asbestos paper sheet known as asbestos felt of suitable quality and thickness, depending on the conditions under which the insulation material is to operate, is combined with cellulosic material by simply using an adhesive to cause combination of the two.
  • a cellulose derivative for example, cellulose acetate
  • the sheet of cellulose acetate may be treated with a varnish comprising an alkyd resin which may or may not contain therein such modifying agents as natural resins, vegetable oils and/or the acids derived
  • the drying oils like linseed, China-Wood oil and the like, or the acids derived from these oils.
  • the asbestos paper is combinedv with the cellulose acetate, preferably under pressure, or pressure and heat, to cause firm adherence and the combined material is either air dried or heat treated to cure the resin as the case may require.
  • a non-resinous adhesive is used as for example, a water soluble glue
  • the sheets may be combined directly under pressure and air-dried.
  • the cellulose acetate it is, of course, understood that other cellulosic materials such as enumerated heretofore may be used.
  • the cellulosic material is employed ina plastic state-which it may be caused to assume by the use of heat and/or pressure and/or solvents and applied to asbestos sheet material using, if necessary, a suitable adhesive to aid in the combination of the materials. After being thus brought together the combined material is oven treated to dry the same and expel solvents, if any are present in the mass.
  • a suitable sizing material for example, starch, casein, etc. may be applied to the asbestos before the adhesive is applied. 'I'his will insure less trouble in removing solvents and prevent the utilization of too much adhesive material.
  • a still further method to make the insulation material is to'prepare a suitable solution of the cellulosic material employed, and spray the latter by means of suitable spray apparatus on felted asbestos as it passes by the former on a. conveyor apron, drying the sprayed material and repeating the spraying operations, it desired or necessary.
  • the combined material may be passed through a bath of the cellulosic material and further coated in this way.
  • felted asbestos in sheet form in connection with cellulosic material of diierent types in a single insulation. That is, the invention not only comprehends the combination of a single cellulosic material with felted asbestos, but where desirable or necessary suitable combinations of different .types of cellulosic material may be used in making the insulation material. For example, regenerated cellulose may be combined with felted asbestos which in turn may be combined with cellulose acetate and the whole if desired further coated or impregnated with insulating varnishes, synthetic resins, etc.
  • a unitary flexible electrical insulation material of high dielectric strength composed of a continuous sheet of cellulose acetate united with a coextensive continuous sheet consisting of ielted asbestos.
  • a unitary flexible insulation material of high dielectric strength composed of a continuous sheet of cellulose acetate united on each side thereof with felted asbestos in sheet form coextensive with said sheet of cellulose acetate.
  • An electrical insulation material comprising a sheet of ielted asbestos faced on each side thereof with a sheet of cellulose acetate.

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  • Insulating Bodies (AREA)

Description

Feb. 8, 193s.
c. F. OBERMAIER 2,107,901
ELElITRICALIv INSULATION MATERIAL Original Filed Nov. 20, 1951.
Fi Q2.
mmmhw C E I LU LOSE ACETATE WWW WM As BE sms mm\m CELLU LOSE ACETATE Fi 2.35.A
WWW/Wm A5 B ESTOS Mmmm CELLULOSE ACETATE ASB ESTO 5 Inventor: Carl P. Obermaier,
w www CLJ Hinctorneg Patented Feb. 8, 1938` UNITED STATES PATENT OFFICE ELECTRICAL INSULATION MATERIAL Carl F. Obermaier, York, Pa., assignor to General Electric Company, a corporation of New York 3 Claims.
The present application is a division of my copending application SerialNo. 576,433, led November 20, 1931, now Patent No. 2,038,378.
This invention relates to electrical insulation 5 material and to methods of making the same.
Asbestos listing,.which is tape Woven from iine asbestos yarn, has been used for some time in the electrical industry as insulation material. This tape has been diiiicult and expensive to'manufacture especially in thin sheets. -Such material as well as the so-called asbestos paper tape possesses very little strength.
In accordance with the present invention asbestos either felted or in the form of a ne paperlike material in sheet form is combined in a suitable manner with a cellulosic material, such as, for example, regenerated cellulose, known in the trade for instance as cellophane, or a cellulose derivative such as cellulose acetate. By the terml cellulosic material as hereinafter used, therefore, it is to be understood that such classes of material as enumerated above are included.
One practical result of my invention is the production of a sheet or tape of combined cellulosic material and felted asbestos which is adapted for use as insulation of wire in cable construction as more fully set forth in the copending application of Carl F. Obermaier and Murray H. Owen, Serial No. 558,535, led August 21, 1931, now Patent No. 2,038,377 and assigned to the assignee of the present invention.
The cellulosic material not only lends strength to the asbestos but the combined material is rendered high in dielectric value due to the cellulosic material and heat resistant due to the felted asbestos. It may be made in the form of sheets, tape, windings, etc. and may be impregnated or coated with such materials as insulating varnishes, synthetic resins and the like, making the whole better in insulation value and eliminating subsequent coating operations Where the material is used for example as a tape in insulating windings of electrical apparatus. In certain cases, the material may consist of a single sheet of cellulosic material combined on one or both sides thereof with asbestos or the asbestos may be sandwiched between a plurality of sheets of cellulosic material and suitably combined therewith.
For a consideration of what is believed to be novel and the invention, attention is directed to the following specification, the accompanying drawing, and the claims appended thereto.
Figure 1, in the accompanying drawing illustrates one modification of my invention, while Figures 2 and 3 illustrate further modifications of the invention.
In accordance with one method of producing the insulation material of my invention asbestos paper sheet known as asbestos felt, of suitable quality and thickness, depending on the conditions under which the insulation material is to operate, is combined with cellulosic material by simply using an adhesive to cause combination of the two. For example, where a cellulose derivative, for example, cellulose acetate is combined with asbestos paper sheet, the sheet of cellulose acetate may be treated with a varnish comprising an alkyd resin which may or may not contain therein such modifying agents as natural resins, vegetable oils and/or the acids derived,
therefrom as for example the drying oils like linseed, China-Wood oil and the like, or the acids derived from these oils. The asbestos paper is combinedv with the cellulose acetate, preferably under pressure, or pressure and heat, to cause firm adherence and the combined material is either air dried or heat treated to cure the resin as the case may require. Wherea non-resinous adhesive is used as for example, a water soluble glue, the sheets may be combined directly under pressure and air-dried. In place of the cellulose acetate it is, of course, understood that other cellulosic materials such as enumerated heretofore may be used.
In accordance with a further method of manufacturing the insulation material of the invention the cellulosic material is employed ina plastic state-which it may be caused to assume by the use of heat and/or pressure and/or solvents and applied to asbestos sheet material using, if necessary, a suitable adhesive to aid in the combination of the materials. After being thus brought together the combined material is oven treated to dry the same and expel solvents, if any are present in the mass.
Where it is desired to prevent the asbestosI sheeting from absorbing too much adhesive a suitable sizing material, for example, starch, casein, etc. may be applied to the asbestos before the adhesive is applied. 'I'his will insure less trouble in removing solvents and prevent the utilization of too much adhesive material.
A still further method to make the insulation material is to'prepare a suitable solution of the cellulosic material employed, and spray the latter by means of suitable spray apparatus on felted asbestos as it passes by the former on a. conveyor apron, drying the sprayed material and repeating the spraying operations, it desired or necessary.
After the asbestos has gained some strength due to the initial spray the combined material may be passed through a bath of the cellulosic material and further coated in this way.
It is Within the scope of the present invention to utilize felted asbestos in sheet form in connection with cellulosic material of diierent types in a single insulation. That is, the invention not only comprehends the combination of a single cellulosic material with felted asbestos, but where desirable or necessary suitable combinations of different .types of cellulosic material may be used in making the insulation material. For example, regenerated cellulose may be combined with felted asbestos which in turn may be combined with cellulose acetate and the whole if desired further coated or impregnated with insulating varnishes, synthetic resins, etc.
Various obvious modifications will occur to those skilled in the art to which the invention pertains, and it is desired to include all such modications within the scope of the appended claims.
What I claim as new and desire to secure by Letters Patent of the United States is:
1. A unitary flexible electrical insulation material of high dielectric strength composed of a continuous sheet of cellulose acetate united with a coextensive continuous sheet consisting of ielted asbestos. 2. A unitary flexible insulation material of high dielectric strength composed of a continuous sheet of cellulose acetate united on each side thereof with felted asbestos in sheet form coextensive with said sheet of cellulose acetate.
3. An electrical insulation material comprising a sheet of ielted asbestos faced on each side thereof with a sheet of cellulose acetate.
CARL F. OBERMAIER.
US6485636 1931-11-20 1936-02-20 Electrical insulation material Expired - Lifetime US2107901A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US6485636 US2107901A (en) 1931-11-20 1936-02-20 Electrical insulation material

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US57643331 US2038378A (en) 1931-11-20 1931-11-20 Electrical insulation material
US6485636 US2107901A (en) 1931-11-20 1936-02-20 Electrical insulation material

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US2107901A true US2107901A (en) 1938-02-08

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2523022A (en) * 1949-12-31 1950-09-19 Gen Electric Reinforced asbestos tape and process of making same
US2561891A (en) * 1949-07-28 1951-07-24 Johns Manville Insulating fabric
US2637673A (en) * 1950-01-30 1953-05-05 Reconstruction Finance Corp Nonwoven film coated fabric
DE1169537B (en) * 1958-09-06 1964-05-06 Calor Emag Elektrizitaets Ag Laminate for electrotechnical purposes
US3531353A (en) * 1966-06-29 1970-09-29 Ppg Industries Inc Method of coating wood

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2561891A (en) * 1949-07-28 1951-07-24 Johns Manville Insulating fabric
US2523022A (en) * 1949-12-31 1950-09-19 Gen Electric Reinforced asbestos tape and process of making same
US2637673A (en) * 1950-01-30 1953-05-05 Reconstruction Finance Corp Nonwoven film coated fabric
DE1169537B (en) * 1958-09-06 1964-05-06 Calor Emag Elektrizitaets Ag Laminate for electrotechnical purposes
US3531353A (en) * 1966-06-29 1970-09-29 Ppg Industries Inc Method of coating wood

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